Roofing System for Buildings

ABSTRACT

A roofing system for buildings includes a plurality of rafters spaced apart across an area to be roofed, each having an upper surface adapted with keying formations and two longitudinal sides from the bottom of each of which a lateral ledge extends. A plurality of infil units are positioned, one between each two adjacent rafters. Each unit is formed from an insulated panel of similar depth to the depth of a rafter and a support layer secured together.

This invention relates to a roofing system for buildings with shallow sloped roof, or a single or double pitched roof.

Accordingly, the present invention is a roofing system for buildings including a plurality of rafters to extend between two supporting locations and spaced apart across an area to be roofed, each rafter having an upper surface adapted with keying formations and two longitudinal sides from the bottom of each of which a lateral ledge extends, a plurality of infil units to be positioned, one unit between each two adjacent rafters, each unit being formed from an insulated panel of similar depth to the depth of a rafter and a support layer secured together, the support layer extending between and seating across adjacent ledges, and a tile to overlie each unit and to lap partially over each of the two adjacent rafters whereat it is secured by a keying element engaging in a keying formation on the corresponding rafter.

Preferably, the joint between the edges of adjacent tiles partially overlapping a rafter are protected by an elongate cover secured into a keying formation on said rafter. Each elongate cover beneficially has a depending key to lock with its respective keying formation on a rafter. Each cover desirably has outer seals along its longitudinal edges to flexibly seal against the surface of the tiles.

Preferably also, the insulating panel of the unit is a plastic material, for example polyisocyranurate (PIR), or similar fire retardant foam, and the support layer is of foamed PVC sheet, bonded to the insulating panel.

Preferably further, the tile is made from foamed Poly vinyl chloride (PVC) sheet, extruded or thermoformed. Beneficially, it has an outer layer of unfoamed PVC with a further outer layer of Acrylic Alloy, (PMMA or equivalent) having weather resistance and colour retention properties. The PIR and PVC plastic material are both desirably fire resistant.

Each rafter is preferably of plastics material of substantially inverted T shape, the stem being of multi-walled construction, the walls being connected at their upper ends and the cross-piece on each side of the stem serving as the lateral ledges. The keying formations on the upper surface of each rafter desirably are formed of three grooves parallel to the longitudinal sides. Each groove may have similar integral locking teeth on opposite walls. The upper surface is preferably coated with a soft PVC. The voids between the walls are filled with PIR, or material with a similar honeycombed structure.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a perspective view of a portion of a roofing system according to the present invention;

FIG. 2 is an exploded cross-sectional view of the system;

FIG. 3 is a enlarged cross-sectional detail of an upper surface of a rafter with a cover above and;

FIG. 4 is an end view of a ridge assembly;

Referring to the drawings, a roofing system for buildings includes a plurality of rafters 10 to extend between two supporting locations, i.e. a ridge and an eave, and spaced apart across an area to be roofed, for example that area defined between two gables. Each rafter 10 has two longitudinal sides 11 from each of which a lower lateral ledge 12 extends. A plurality of infil units 14 are provided to be positioned one unit 14 between each two adjacent rafters 10. Each unit 14 is formed from a rectangular block forming an insulated panel 18 of similar depth to the depth of a rafter 10 and a rectangular sheet forming a support layer 20 secured together. The layer 20 extends between and seats across two adjacent ledges 12.

A tile 16 is provided to overlie each unit 14 and to lap partially over each of the two adjacent rafters 10 whereat it is secured by a keying element 23 engaging in a keying formation on the corresponding rafter 10. Each tile 16 is provided with apertures adjacent to each lateral side through which the elements 23 pass, The apertures are slots to allow for expansion. The joint between the edges of adjacent tiles 16 partially overlapping a rafter 10 are protected by an elongate cover 24 secured into a keying formation on said rafter 10. Each elongate cover 24 has a depending key to lock with its respective keying formation on a rafter 10. Each cover 24 has outer seals 24A along its longitudinal edges to flexibly seal against the surface of the tiles 16.

Each tile 16 and support layer 20 is of plastics material, the tile 16 being of cellular or foamed rigid poly-vinyl-chloride (PVC) and coated on its outer side with a skin of unfoamed PVC, and an Acrylic compound (PMMA or equivalent) or other polymer having suitable characteristics together with having weathering resistance and colour retention characteristics, and the layer 20 has fire retardant characteristics. The panel 18 is also of plastics material, for example of Polyisocyranurate (PIR) or other cellular insulating polymer. The panel 18 is bonded to the layer 20, the bonding being a natural characteristic of the foamed material. The PIR and PVC materials are fire retardant.

Each rafter 10 is of plastics material of substantial inverted T shape, the stem 10A being of multi-walled construction, the walls being connected at 10B at their upper ends with the voids therebetween being filled with PIR and the cross-piece 10C on each side of the stem 10A serving as the lateral ledges 12.

The keying formations 26 on the upper surface of each rafter 10 are formed of three grooves 28 parallel to the longitudinal sides. Each groove 28 has similar integral locking teeth on opposite walls. The upper surface is coated with a soft PVC. The voids between the walls are filled with PIR, or material with a similar honeycombed structure.

Associated components for use with the system comprise:—

-   -   1. ridge covers as shown in FIG. 4 made from extended foamed PVC         coated on its outer side with a skin of PVC and Acrylic compound         having weathering resistance and colour retention         characteristics, length cut to suit ridge, in conjunction with         an extended PVC inner ridge connector having fire retardant         characteristics fixed to the rafter ledges of a complementary         length. When in situ the outer and inner ridge parts are locked         together enclosing the rafter 10, tile 16 and unit 14. Vent         profiles can be incorporated into the ridge cover and ridge         connection during thermoforming. This latter in conjunction with         the eaves facia board extrusion holds the whole roof         construction in its skeleton form before the units 14 are         slotted into place between the rafters 10 and the tiles with         associated jointing covers are locked in place;     -   2. eaves facia board, in extruded PVC, is designed to support         the units 14 at the eaves, with pinning facilities to avoid         upward suction caused by wind movements; air seal and a standard         facia board to allow the attachment of guttering. While the         rafter 10 is pinned to the eaves facia board so also is the         unit. The facia profile itself is pinned to the appropriate part         of the building to absorb downward loading;     -   3. gable end assembly in extruded PVC, designed to allow the         edges of the units 14 to be housed in appropriate weather-tight         recesses, with a suitable junction moulding at the apex; it is         fixed to the gable end of the building wall structure;     -   4. end wall abutment, in extruded PVC, to allow adequate sealing         between the units 14 and an end wall. The end wall abutment is         sealed to the wall and the unit slides into an appropriate         weather-tight recess;     -   5. Thermoformed gullies.     -   6. End pieces are provided to close off the extruded components         otherwise open.

The rafter 10 may alternatively be of folded galvanised sheet metal, the centre of which is filed with PIR.

In use, a roof is formed using the roofing system as above described in positioning the rafters 10, locating the units 14 thereon and using the associated components as required to complete a roof. The roofing system can accommodate dormer window arrangements with gullies formed of thermoformed PVC sheeting.

The invention has resulted from the development of the concept of approaching the roofing of domestic housing by “unitising” and including all the necessary insulation required to meet the most up to date EU specifications, both heat retention and air tightness. Tolerance allowances are made for the expansion of the components in situ. The length of each unit will either be two metre or the full pitch length of the roof to be covered. The rafters 10 are designed to take the weight of the units 14 with built in allowances for expansion and the possible weight of snow, ice or solar panels. The supporting locations may be the apex of the rafters of a hip part of a roof.

The outer layer may be profiled to a required design.

Variations and modifications can be made without departing from the scope of the invention described above. 

1-15. (canceled)
 16. A roofing system for buildings comprising a plurality of rafters to extend between two supporting locations and spaced apart across an area to be roofed, each rafter having an upper surface adapted with keying formations and two longitudinal sides from the bottom of each of which a lateral ledge extends, a plurality of infil units to be positioned, one unit between each two adjacent rafters, each unit being formed from an insulated panel of similar depth to the depth of a rafter and a support layer secured together, the support layer extending between and seating across adjacent ledges, and a tile to overlie each unit and to lap partially over each of the two adjacent rafters, and keying elements engaging and securing the tile to keying formation on the corresponding rafter, the keying formations on the upper surface of each rafter being formed of three grooves parallel to the longitudinal sides.
 17. A roofing system according to claim 16, further comprising an elongate cover secured into a keying formation on said rafter, the elongated cover overlapping and protecting the joint between the edges of adjacent tiles partially overlapping a rafter.
 18. A roofing system according to claim 17, wherein each elongate cover comprises a depending key adapted to lock with its respective keying formation on a rafter.
 19. A roofing system according to claim 17, wherein each cover comprises outer seals along its longitudinal edges to flexibly seal against the surface of the tiles.
 20. A roofing system according to claim 18, wherein each cover comprises outer seals along its longitudinal edges to flexibly seal against the surface of the tiles.
 21. A roofing system according to claim 16, wherein the insulating panel of the unit is a plastic material and the support layer is of foamed plastic material bonded to the insulating panel.
 22. A roofing system according to claim 21, wherein the plastics material is Polyisocyranurate (PIR).
 23. A roofing system according to claim 16, wherein the tile is made from foamed Polyvinylchloride (PVC) sheet, extruded or thermoformed.
 24. A roofing system according to claim 23, wherein the tile has an outer layer of unfoamed PVC with a further outer layer of Acrylic Alloy, (PMMA or equivalent) having weather resistance and colour retention properties.
 25. A roofing system according to claim 24, wherein the plastic material of the insulating panel, the support layer and the tile are fire resistant.
 26. A roofing system according to claim 16, wherein each rafter is an elongated member of plastics material of substantially inverted T shape, the stem being of multi-walled construction with the walls being connected at their upper ends and the cross-piece on both sides of the stem serving as the lateral ledges.
 27. A roofing system according to claim 26, wherein each groove has similar integral locking teeth on opposite walls.
 28. A roofing system according to claim 27, wherein said upper surface is coated with a soft PVC.
 29. A roofing system according to claim 26, wherein voids between the walls are filled with PIR, or material with a similar honeycombed structure. 